The present invention relates to bioabsorbable, porous, reinforced tissue engineered implant devices for use in the repair of soft tissue injury such as damage to the pelvic floor and methods for making such devices.
Individuals can sometimes sustain an injury to tissue, such as musculoskeletal tissue, that requires repair by surgical intervention. Such repairs can be effected by suturing the damaged tissue, and/or by mating an implant to the damaged tissue. The implant may provide structural support to the damaged tissue, and it can serve as a substrate upon which cells can grow, thus facilitating more rapid healing.
One example of a fairly common tissue injury is damage to the pelvic floor. This is a potentially serious medical condition that may occur during childbirth or from complications thereof which can lead to sustaining an injury of the vesicovaginal fascia. Such an injury can result in a cystocele, which is a herniation of the bladder. Similar medical conditions include rectoceles (a herniation of the rectum), enteroceles (a protrusion of the intestine through the rectovaginal or vesicovaginal pouch), and enterocystoceles (a double hernia in which both the bladder and intestine protrude). These conditions can be serious medical problems that can severely and negatively impact a patient both physiologically and psychologically.
These conditions are usually treated by surgical procedures in which the protruding organs or portions thereof are repositioned. A mesh-like patch is often used to repair the site of the protrusion.
Although these patches are useful to repair some herniations, they are usually not suitable for pelvic floor repair. Moreover, patches or implants that are made from a non-bioabsorbable material can lead to undesirable tissue erosion and abrasion. Other implant materials, which are biologically derived (e.g., allografts and autografts), have disadvantages in that they can contribute to disease transmission, and they are difficult to manufacture in such a way that their properties are reproducible from batch to batch.
Various known devices and techniques for treating such conditions have been described in the prior art. For example, European Patent Application No. 0 955 024 A2 describes a intravaginal set, a medical device used to contract the pelvic floor muscles and elevate the pelvic floor.
In addition, Trip et al (WO 99 16381) describe a biocompatible repair patch having a plurality of apertures formed therein, which is formed of woven, knitted, nonknitted, or braided biocompatable polymers. This patch can be coated with a variety of bioabsorbable materials as well as another material that can decrease the possibility of infection, and/or increase biocompatibility.
Other reinforcing materials are disclosed in U.S. Pat. No. 5,891,558 (Bell et al) and European Patent Application No. 0 274 898 A2 (Hinsch). Bell et al describe biopolymer foams and foam constructs that can be used in tissue repair and reconstruction. Hinsch describes an open cell, foam-like implant made from resorbable materials, which has one or more textile reinforcing elements embedded therein. Although potentially useful, the implant material is believed to lack sufficient strength and structural integrity to be effectively used as a tissue repair implant.
Despite existing technology, there continues to be a need for a bioabsorbable tissue repair implant having sufficient structural integrity to withstand the stresses associated with implantation into an affected area.
This invention relates to bioabsorbable, porous, reinforced tissue implant, or xe2x80x9cscaffold,xe2x80x9d devices for use in the repair or regeneration of diseased or damaged tissue, and the methods for making and using these devices. The implants comprise a bioabsorbable polymeric foam component having pores with an open cell pore structure. The foam component is reinforced with a material such as a mesh. Preferably, the implant has sufficient structural integrity to enable it to be handled in the operating room prior to and during implantation. These implants should also have sufficient properties (e.g., tear strength) to enable them to accept and retain sutures without tearing. Desirable properties are imparted to the implant of the invention by integrating the foam component with the reinforcement component. That is, the pore-forming webs or walls of the foam component penetrate the mesh of the reinforcement component so as to interlock therewith. The implant may include one or more layers of each of the foam and reinforcement components. Preferably, adjacent layers of foam are also integrated by at least a partial interlocking of the pore-forming webs or walls in the adjacent layers.
The reinforcement material is preferably a mesh, which may be bioabsorbable. The reinforcement should have a sufficient mesh density to permit suturing, but the density should not be so great as to impede proper bonding between the foam and the reinforcement. A preferred mesh density is in the range of about 12 to 80%.
The invention also relates to a method of preparing such biocompatible, bioabsorbable tissue implants. The implants are made by placing a reinforcement material within a mold in a desired position and orientation. A solution of a desired polymeric material in a suitable solvent is added to the mold and the solution is lyophilized to obtain the implant in which a reinforcement material is embedded in a polymeric foam.
The implant may be used as a tissue implant, such as to reinforce a patient""s pelvic floor, or other soft tissue regions where a tear has contributed to herniation.